Tracy,

I didn’t make myself very clear.  The two taps are in the rear of the plenum chamber.  Are you using just one silicone hose from the plenum chamber and splitting it just before the EC-2?  If my two (possibly different length) hoses are bringing pulses at different times into the two MAP ports on the EC-2, could that possibly confuse it??   Also, how steady should the manifold pressure read when the engine is off?  Is the one to one and half tenths mentioned earlier an indication that they should be repaired/replaced?

 

Bill B

On Tue, Mar 30, 2010 at 7:56 PM, Bill Bradburry <bbradburry@bellsouth.net> wrote:

I bought a couple of fuel filters today.  Before I install them I have a
couple of questions.
I have two taps into the intake manifold about an inch apart.  Each of these
taps connect to completely separate lines(one of them has a "T" in it which
goes to the fuel pressure regulator) which go to the two separate inlets on
the EC-2. These two lines are probably of different lengths, and the one has
a "T" in it.  So any pulses could get to the EC-2 at different times even
though they originate from the same place.
Question:  should I "Y" these two lines together into the same filter and
then back out and separate them to go to the EC-2 so the pulses are more
"homogenized" between the two inlets to the EC-2, or keep them separate as
before?
Is this going to slow down the response to a throttle change and cause the
engine to "bog" when the throttle is first opened?  It occurs to me the
factory probably solves this problem with the throttle position sensor which
we don't have.

I am interested in Tracy's take on this since he knows how his system
operates.  I am assuming that we need to do this in the first place because
his system calculates so fast that the pulses cause a problem???

Subject: [FlyRotary] Re: FLIGHT DATA 1

I used small fuel filters in the MAP sensing line.  I soldered the end
closest to the intake manifold shut and then drilled a small hole through
the solder.  This hole was small enough to cause instability (surging) of
the engine at idle.  The hole through the solder was successively drilled
larger until the surging stopped.  The resulting damping system has been in
use on my plane for several years now.  I haven't tried removing it to see
if the upgraded EC2's don't need this.  It's been long enough that I can't
remember what size of hole I ended up with, although that would be easy
enough to measure next time the cowl is off.

Steve Boese


________________________________________
From: Rotary motors in aircraft [flyrotary@lancaironline.net] On Behalf Of
Bill Bradburry [bbradburry@bellsouth.net]
Sent: Monday, March 29, 2010 9:37 PM

Subject: [FlyRotary] Re: FLIGHT DATA 1

I have heard of others using some kind of expansion chamber like this, but
Don is the first I have heard of including a restriction in the line as
well.  He got an improvement with the restriction before he added the
expansion chamber.  I wonder if both would be needed to dampen out the
pulses?

Bill B